A simple walkie-talkie circuit running off an Arduino Nano. Utilizes a BJT to amplify the microphone voltage and transmits the radio signal through a nRF24L01 series Transceiver.
Single M5Stack Cardputer ADV HAT integrating CC1101 sub-GHz radio, nRF24L01+ PA/LNA 2.4GHz radio, LoRa RA-02, and PN532 NFC with shared host interface, 3.3V power distribution, decoupling, and RF layout constraints.